It's a bug fixer (who knew?) There was some confusion that it added hi-res movies and improved music, but that was a typo in the UK version of the patch. The things will be released as a seperate update in a day or two, they say. Here's the readme:

Corrects a crash issue at the beginning of the dialogue after entering the Harbringer
Corrects a crash issue when transitioning between B-4D4 to the main character after Czerka Mainframe quest on Telos (light side)
Corrects an art issue with NPCs that appear in the mine foreman's log on Peragus
Corrects a geometry issue inside the Jekk Jekk Tarr bar on Nar Shaddaa
Corrects an issue with ATI Radeon cards being incorrectly reported in the swinfo.txt
Corrects an issue with Atton missing from force cage in the Telos Academy
Corrects swoop race forfeiting issue. Players can now win races after forfeiting a race.
Corrects an issue with the swoop bike getting stuck in air in the swoop race mini-game
Corrects stuck issue when reboarding Ebon Hawk on Nar Shaddaa
Corrects a text/voice mismatch in Kreia's dialogue on Malachor
Corrects a scripting issue with Batano quest on Telos (light side)
Corrects a scripting issue with Devaronian conversation on Telos
Updates a journal entry for "A Hidden Power" quest on Korriban
Updates a journal entry for the "Fuel Sabotage" bonus mission on Telos
Master Vash’s corpse will now yield a lightsaber if you have a lightsaber when you kill him on Korriban (dark side)
Khoonda Gun Turrets will no longer appear if you destroy them on Dantooine (dark side)
Reduced the repetition of party members' voice lines when opening doors and containers
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KNOWN ISSUES
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If you experience a crash when patching the game in Windows 98 or Windows ME, please make sure that you reboot your system before attempting to repatch the game.
Please reboot the computer if any issues are encountered during the patching process.